A Symmetric Trajectory Algorithm for Cooperative Secure Communication with Dual UAV

In this paper, we investigate a novel model of an Unmanned aerial vehicle(UAV) secure communication, where a UAV base station(UAV-B) moves around to communicate with desired user on the ground while another friendly UAV jammer(UAV-J) in the area jams the eavesdroppers on the ground to protect communications of the desired users. Different from the classical UAV-assisted secure communication, we observe that there is a symmetry relation between the UAV-B and UAV-J. Based on this fact, we modify the original objective function. Specifically, we maximize the minimum worst-case system data rate among the users and eavesdroppers within each period by jointly adjusting UAV trajectories and user scheduling. As, the optimization problem is non-convex with coupled optimization variables, we decompose the optimization problem into two subproblems and use alternating iteration algorithm and successive convex approximation techniques to solve it. Compared with existing schemes, the proposed algorithm has an obvious advantage in the secrecy rate.